Squib switch



Jan. 5, 1960 R. GEBALLE 2,920,166

SQUIB SWITCH Filed Jan. 11, 1950 FIG.I

n/la

INVENTOR.

RONLD GEBALLE ATTORNEY United States Pater-1t() SQUIB SWITCH RonaldGeballe, Seattle, Wash., assignor to the United States of America asrepresented by the Secretary of the Navy Application January 11, 195o,serial N6. 137,996

6 claims. (ci. zoo-142) The present invention relates broadly to anelectrical circuit closer, and more particularly to a switch capable ofcarrying a relatively heavy current, of the order of ten amperes ormore, for example, but which nevertheless may be closed by relativelyweak impulses, such as radio signals with moderate amplification.

' Heretofore devices for closing circuits that carry relatively heavycurrents, by remote control and/ or actuated by very small electricalimpulses, have been complicated and expensive, and often not entirelyreliable, because they usually included one or more sensitive relaysthat were correspondingly sensitive to mechanical shocks and easilyderanged byv handling. The present invention makes it possible tocontrol even a very heavy electrical current vby Y'very simpleY means,completely free from delicate apparatus-such as relays, by making useofan explosive charge t o do'the actual'mechanical workinvolvedinuclosing the switch-said explosive charge requiring onlylarelatively" vtiealcelectrical'impulsel for its ignition. 7,. f p.

' An object of'the present invention is thereforelto'p'rovide a switchof this kind, wherein the actuation is accomplished by the explosion ofa squib, which causes the switch members to move, relatively, intocontact-making condition.

A specific object of the invention is to provide a switch which consistsessentially of two conductors located near one another, together with anexplosive charge means for detonating said charge. Explosion of thecharge has the purpose of forcing a portion of one of the conductorsinto electrical contact with the other, by reason of the gas pressurethus produced. Preferably one of the conductors is hollow and enclosesthe explosive charge, whereby the explosion causes said hollow conductorto expand and in so doing to come into permanent contact with the otherconductor, thus in effect closing a switch.

Another object is to provide a strong, sealed, watertight enclosure fora switch of this type, to make it suitable for underwater use.

Other objects and many of the attendant advantages of this inventionwill be appreciated readily as the same becomes understood by referenceto the following detailed description, when considered in connectionwith the accompanying drawings, wherein:

Fig. l is a side elevation of a switch unit, embodying the invention,and including a sealed case or housing;

Fig. 2 is a longitudinal axial section through said unit, showing thestructure with the switch open;

Fig. 3 is a corresponding fragmentary sectional vi'ew, showing theswitch in closed condition; and

Fig. 4 is an end view of the device.

Referring rst to Figs. 1 and 4, the case or housing 1, which may bethick-walled and made of strong metal, such as steel, has a tightlyfitting cover 2, held thereto in any desired way, for example by capscrews 3. Watertightness may be assured by a suitable coating such asGlyptal varnish, applied to the abutting surfaces before the screws aretightened.

A screw plug 9 is threaded into the said cover 2, and wires 10 and 11enter the case 1 through said plug, which affords means for providing atight seal around the wires by suitable packing, as shown at 17, Fig. 2,for example.

The case 1 constitutes one terminal of the switch, and a suitableconnection may be made thereto in any desired way. The other terminal ofthe switch s the insulated wire 16 which enters the housing 1 throughthe screw plug '12, threaded as shown at 13, suitable packing 15, Fig.2', being provided to make a proper seal.

Referring now to Fig. 2, it will be seen that the cap screws l3 enterthreaded bores such as 19 in the cylindrical wall of case '1. The otherend of this case 1 is closed water-tightly by a cylindrical member 4having an enlarged end or flange 20, fitting into a corresponding borein case 1, as shown. The parts 1 and 20 may be connected by a press-fitor by welding, or both, as may be necessary or desirable in any giveninstance. As the entire unit may be intended for use submerged in seawater, appropriate coatings may be provided to prevent corrosion and/ orto assure a water-tight and pressure-tight joint between head 2 and case1, etc.

A metal tube 5, having a relatively thin wall, is located partly in thebore 6 of cylinder 4, but insulated therefrom by the ring 7 and the cap8, which may be made of any desired insulating material, for example,rubber or other plastic,

Conductor 16 has its bare inner end 18 wound several timesfarond theexposed end of tube 5 and electrically and mechanically secured theretoin any suitable way, as by welding or soldering. t t.

A squid 14, also commonly'known as an electric blasting cap, havinglead-in wires 10-and 11` associated therewith,`.i's'. mounted within thetube 5, and preferably about half-way between ring 7 and cap 8. A plug2,1 of compacted cotton bers or the like may be placed at the inner endof the tube 5 to locate the squib 14 correctly, and additional packing22 may be forced around the wires 10 and 11 to keep them in place withinthe tube 5.

The operation is as follows: When a suitable tiring impulse isintroduced to the squib 14 through wires 10 and '11, said squib willexplode, and in so doing will cause the tube 5 to expand until aconsiderable part of its outer surface is in intimate contact with thewall of the bore 6, somewhat as shown in Fig. 3, thus establishing alowresistance electrical connection capable of carrying a heavy current.

Preferably tube 5 is of soft relatively inelastic metal, such as copper,and thin enough to expand readily. The outer cylinder 4 is relativelyrigid, so that it will not expand appreciably when the squib is red. Theelectrical result of the expansion of tube 5 is that wire 16 becomesgrounded to cylinder 4, and thus in effect closes a switch. Wheremechanical resistance to external disturbances or other influences isnot important, for example, if the switch is to be used when surroundedby ordinary air, instead of when submerged in sea water, the protectivecase 1 may be omitted.

It is to be understood that it is immaterial from what source the squibis detonated. A direct connection to a suitable battery or generator maybe used, or a relay or amplifier initially operated by a radio or lightsignal, or by a telegraphic wire signal may be used, the precise circuitconstituting no part of the present invention.

It will be obvious that while the invention has been disclosed asdependent on ythe expansion of an inner tubular conductor by the squib,it is likewise possible to reverse the relationship o-f the rigid andyieldable elements, and to cause the squib explosion to contract theouter tube against the outside of an inner rigid conductor. Suchconstruction, however, is mentioned only as a possibility, and exceptwhere unusual conditions make it desirable, or essential, would not beutilized as'it is more complicated than the preferred form alreadydescribed in detail.

An important feature, however, regardless of its exact structure, isthat a relatively feebleimpulse, sufficient only to ignite the squib,Will'serve to close a circuit capable of heavy current ow, so that anelectric motor or other apparatus may be started directly by saidcircuit., The present device thus lends itselfreadily to remote controlof such apparatus.

The heavy case 1,V when used, makes it possible to operate in greatdepthsof sea water, and/ or in the presence of high pressures resultingfrom explosions of weapons such as atomic bombs, Vdepth charges, mines,etc;

Obviously many modifications and variations ofthe present invention arepossible inthe light of the above teachings.r Itis therefore to beunderstood that within the scope ofthe appended claims the invention maybe practisedotherwise than asspeciiically described;

What is claimed is:

l. A switch comprising an outer cylindrical conductor, an innercylindrical'conductor spaced therefrom, and an explosive device withinthe inner conductor, whereby said inner conductor will be inelasticallydeformed into` electrical contact with the outer conductor whenexplosion of said device occurs.

2. A switch comprising two electrically conductive elements, one ofwhich is substantially tubular and encloses a portion of the other butis out of electrical contact therewith, one of said elementsbeinginelastically deformable to an extent suicient to make permanentelec-l trical contact with `the other, and an explosive chargeso locatedthat 'the inelastically deformable element lies be;A tweenA itand" theother element, whereby detonation of saidcharge'will force' aportion ofsaid deformable ,ele, mentinto permanent electrical contactwith theother elementi" 3; A switch"l comprisingtwo electrically conductive'tubular elements, one of vwhich is within a portion oft'the 4 boreoftheother,v butout -ofelectricalcontact--therewith, an explosive chargewithin the bore of the inner element, and means for igniting saidcharge, said elements being spaced apart a distance less than thepermanent deformation of the inner element producible by the explosionof said charge.

4. A switch for under-water use, comprising a watertight metal case,havingk a bore in a portion thereof, a tubular metallic element in saidbore but out of electrical contact with the case, and-an explosivecharge within said element'and, of sufficient strengthrto force theouter surface of the tubular element into permanent contact with theinner wall of said bore upon detonation of theexplosive charge.,

5. A switch as dened in claim 4, wherein the explosive charge is.anelectrically ignitable squib.

6. A switch comprising two electrically conductive elements, one ofwhich substantially encloses a portion of the .other but is outofelectrical contact therewith, one of said" elementsbeing inelasticallydeformable to an ex.-A tent suicient to make permanent electricalcontact with the other, andl an explosive chargeso located that theinelastically deformable element lies between it and thek other element,whereby4 detonation of said charge will force a portion of vsaiddeformable element into permanent electrical contact with the otherelement.

References Cited'in the le of 'this patent UNITEDV STATES PATENTS

